I have parts to make my switch, but before I go there does anyone know if a COTS item is available, a basic on/off dusk/dawn 120vac switch that has the light sensor (photocell), BUT, I need it to be a dawn-to-dusk 'on' switch. I need to control some outdoor fountains, on during the day, off at night. Any suggestions?

 

Personally I don't know of anything Off The Shelf that does what you're asking. That doesn't mean they don't exist, they might. An alternative OTS would be a timer that turns on at a given hour of the day and turns off at a later hour.
Other alternatives would be to get a standard D2D photo sensor and hook it up to a SPDT relay. When the sensor shuts off in the morning it would drop out a relay and close the NC (Normally Closed) contacts and you'll have your exact requirements, On at Daybreak, Off at Dusk.
That's all I got. Timer, or a relay added to a standard Dust To Dawn sensor.

 

Photocell switches are very common in the industrial control world. Reliable, adjustable, but *not* hobbyist-cheap. I'm sure others around here have favorites to recommend.

ak

 

That's one thing that AliX is good for, cheap modules!

Just a few but many more on their site...

 

A word of caution about the items shown in post #4! There is no mention of current rating, and based on the appearance of the leads, and the size of the device package the wire is about #20, at most. So a relay may be required to switch any load.

 

Google "Timer dawn to dusk"
Available through many retailers under 12 dollars.

 

Google "Timer dawn to dusk"
Available through many retailers under 12 dollars.

Did you find any that are dawn-to-dusk ?

da-du is a daytime NC item, I cannot find any.
du-da is a nighttime NC item, that's all I find.

I need a da-du NC item, so at night the fountains turn off.

 

Hello,

With a change over contact of a relays, you can determine the behaviour of the load.
https://www.homemade-circuits.com/how-to-make-light-activated-day-night/amp/

Bertus

 

Did you find any that are dawn-to-dusk ?

It's a timer. You choose when you want it to come on and when you want it to shut off.
ON @ 06:00
OFF @ 18:00
Or any time you like. Programmable timers can have several ON and OFF times during a single day if you should ever need.

 

Hopefully this will clear it up for you:
View attachment 357485

 

AT one time, long ago, I did modify one of those photo-electric devices.
The way some of them, even currently, work is that a photo-resistive sensor has a low resistance when illuminated, and so a nichrome heater causes a bimetal arm to flex and open a set of contacts. My modification was to move the "fixed contact" to the opposite side of the bimetal arm that carried the moving contact. That particular package was rather simple to re-arrange.
Probably a revision of the simple bias circuit for a current technology DAY/NIGHT switch could have the LDR sensor providing the TRIAC switch-on voltage instead of removing it. THAT will be simpler than adding a relay that would be activated all night.
Of course it would require a bit of modification of the module.

 

I need a da-du NC item, so at night the fountains turn off.

Timer

 

It's a timer. You choose when you want it to come on and when you want it to shut off.
ON @ 06:00
OFF @ 18:00
Or any time you like. Programmable timers can have several ON and OFF times during a single day if you should ever need.

Timer is no good, because I don't want my fountain off at 5pm during the summer, but I do want it off at 5pm winter.
Hence why it has to be photocell. And I have used timers for years, their clocks have decent amount of drift requiring manual adjusting, something I dont care to do.

And for the other posts, thanks for the schematic tips, but I already have the parts to make what I need, was trying to avoid having to make it. I always seek COTS 1st, then make it 2nd.

 

Timer is no good, because I don't want my fountain off at 5pm during the summer, but I do want it off at 5pm winter.

You want what you want. And that's fine.
I have a timer in my living room. In the summer time the living room lights come on at 8:30 PM. They go off at 11:15 PM. As the days shorten I reset the timer to come on at 6:30 PM but still off at 11:15 PM. Days shorten even more and I reset the timer to come on at 4:30 PM. Come spring time the process reverses. It's easy enough to reset the settings. But I understand. You want a photosensor. You deserve to have what you want the way you want it. That's why I drew the diagram in post #10. Since a standard photo cell will turn ON at night it can turn on a relay that disables the power to the pump(s). In the morning the sensor shuts off dropping the relay out and thus re-energizing the pump(s).

Can't point to a specific device but I have seen, or heard of, timers that adjust with the seasons so that lights can come on via a timer and keep step with the daylight progression and recession. I'm certain you will find the solution that suits your wants/needs.

I DO have a photosensor that turns on driveway lights. It suits me fine the way it is. It would be just as easy to invert the output by use of a relay. Has to be Double Throw. Single pole or double pole doesn't matter, you're only going to use one pole. But it has to be double throw because it has to be OFF when it's ON.

 

You want what you want. And that's fine.
I have a timer in my living room. In the summer time the living room lights come on at 8:30 PM. They go off at 11:15 PM. As the days shorten I reset the timer to come on at 6:30 PM but still off at 11:15 PM. Days shorten even more and I reset the timer to come on at 4:30 PM. Come spring time the process reverses. It's easy enough to reset the settings. But I understand. You want a photosensor. You deserve to have what you want the way you want it. That's why I drew the diagram in post #10. Since a standard photo cell will turn ON at night it can turn on a relay that disables the power to the pump(s). In the morning the sensor shuts off dropping the relay out and thus re-energizing the pump(s).

Can't point to a specific device but I have seen, or heard of, timers that adjust with the seasons so that lights can come on via a timer and keep step with the daylight progression and recession. I'm certain you will find the solution that suits your wants/needs.

I DO have a photosensor that turns on driveway lights. It suits me fine the way it is. It would be just as easy to invert the output by use of a relay. Has to be Double Throw. Single pole or double pole doesn't matter, you're only going to use one pole. But it has to be double throw because it has to be OFF when it's ON.

I have installed some of those devices that use sunset to start a timer for some number of hours. I have also installed the simple solar switch to switch lights on during darkness.
ADDING A RELAY would not be physically simple in any of those installations!! First, the relay must be rated for constant operation while carrying the application's load, which may be several amps. Then, also, the relay must be in an enclosure suitable for the application. THAT is often not simple, because in most applications the enclosure must be both weather-proof and tamper resistant. Those requirements are often not simple or cheap to meet.

 

@MisterBill2 has made some good points. But in the spirit of answering your question for an application the way you want it - I gave you my answer. However, back in post #2

Timer, or a relay added to a standard Dust To Dawn sensor.

A timer would be the most expedient solution. Others have suggested the same. (see posts #6, 9 & 12)

 

ADDING A RELAY would not be physically simple in any of those installations!! First, the relay must be rated for constant operation while carrying the application's load, which may be several amps.

Not so hard to find.

Then, also, the relay must be in an enclosure suitable for the application. THAT is often not simple, because in most applications the enclosure must be both weather-proof and tamper resistant.

It's a foregone conclusion that a projects box would likely be necessary. But it doesn't need to be outdoors. It could be indoors, or if outdoors, a projects box that is outdoor rated shouldn't be that difficult to find. Tamper resistant? I suppose. Depends on how and where the box is. By "Tamper resistant" I think of something you'd need a special screwdriver bit to open it, or a box with a locked lid. If this is a public item then yes, I'd agree 100% it needs to resist being tampered with. But if it's a home owner project unlikely to be messed with strangers - something with a latch should do. And the wiring of such a relay can be hardened to prevent contact with live wires.

I'm certain someone mentioned that we don't know how much power the pump(s) draw. That's also a critical consideration. My cat's water dish has filtration and a pump. It runs from a 5V phone charger. Very low power. But a pond pump similar to what I have in my yard draws a lot more power than a wall wart can provide. It has a big 12VAC transformer. And that can run fairly warm. SOME of the relays I have on hand could run that pump. But something like a washing machine motor - that'd eat up any relay I have laying around. MisterBill2 mentions "while carrying the application's load, which may be several amps". Maybe that's what I'm thinking of someone mentioning power draw.

 

Hopefully this will clear it up for you:
View attachment 357485

This is what I was going to suggest. Just make sure your relay can handle the load. Thanks Tony for the drawing.

Ron

 

The startup load for a typical fountain pump is longer lasting as well as being a medium inertia load. So the contacts need to handle the heat from the starting inrush.

 

I would be lucky to see inrush of 1-2A on these small fountain pumps. ~800gph 60w. The relays I have are rated 240ac 30A.

Looks like i'll be making it. Even the pic in post #18, will work, but I have to make it.